NSCoder not working with NSArray

Question

I am trying to implement the NSCoder methods encodeWithCoder and initWithCoder for a custom object i have created which has a child array of custom objects. Both custom objects employment the above mentioned methods but after the top level object has been decoded the value for the array is always nil.

Both objects implement the methods below, The dictionary and the arrays or popular from a library i have for getting field names and turning objects into dictionaries. I have checked that encodeObject is being called on the Array and at this time the array is not nil. I have equally checked that the decode method is receiving nil on the other side..

I can't work out where i am going wrong? Am i correct is assuming that so long as child array objects implement the protocol i should be fine to do it this way?

- (void)encodeWithCoder:(NSCoder *)aCoder{
    NSDictionary* dictionary = [jrModelBinder unBind:self];
    for(NSString* field in dictionary)
    {
        id val = [self valueForKey:field];
        [aCoder encodeObject:val forKey:field];
    }
}

-(id)initWithCoder:(NSCoder *)aDecoder{
    if(self = [super init]){
        NSArray* fields = [jrModelBinder propertyNames:self];
        for(NSString* field in fields)
        {
            id val = [aDecoder decodeObjectForKey:field];
            [self setValue:val  forKey:field];
        }
    }
    return self;
}

Don't forget to call `[super initWithCoder:]` in `initWithCoder`. — quellish, Sep 21 '14 at 18:37
Please update your question with your implementation of `decodeWithCoder:` as well. — quellish, Sep 21 '14 at 18:46
I do not implement decodeWithCoder, it does not seem to be part of the NSCoder protocol? — Jarmez De La Rocha, Sep 21 '14 at 19:25
If you are saving to file, you can quicklook (tap space in finder) on the plist and get an idea of what is being saved. It might help you understand what is happening. — combinatorial, Sep 21 '14 at 19:54

score 0 · Answer 1 · answered Sep 21 '14 at 20:14

I misunderstood your question before:

NSKeyedArchiver/Unarchiver should encode and decode NSArrays and NSDictionaries with no problem.

But I think since your array itself contains custom Objects which implements below 2 functions:

- (id)initWithCoder:(NSCoder *)aDecoder
- (void)encodeWithCoder:(NSCoder *)enCoder

Try using below for array

NSData * encodedData = [NSKeyedArchiver archivedDataWithRootObject:someArray];

Also use NSKeyedUnarchiver to decode.

You may have to save the data in File or NSDefault. – bllakjakk Sep 21 '14 at 20:17 — bllakjakk, Sep 21 '14 at 20:17

NSCoder not working with NSArray

1 Answers1